Fix https://issues.apache.org/bugzilla/show_bug.cgi?id=54971
Pass the calculated location to AplicationPart rather than it having to recalculate it every time. Now correctly handles relative locations.

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1486939 13f79535-47bb-0310-9956-ffa450edef68